Bacteriology of preserved stallion semen and antibiotics in semen extenders

• Published in: Theriogenology 1998-09, Vol.50 (4), p.559-573
• Main Authors: Varner, D.D, Scanlan, C.M, Thompson, J.A, Brumbaugh, G.W, Blanchard, T.L, Carlton, C.M, Johnson, L
• Format: Article
• Language: English
• Subjects: Amikacin - administration & dosage; Animals; Anti-Bacterial Agents - administration & dosage; antibiotics; bacteriology; Clavulanic Acid - administration & dosage; Colony Count, Microbial; equine; Gentamicins - administration & dosage; Horses; Male; Penicillins - administration & dosage; Polymyxin B - administration & dosage; Semen - microbiology; semen extender; Semen Preservation; Sperm Motility; Spermatozoa; spermatozoal motility; Streptomycin - administration & dosage; Ticarcillin - administration & dosage
• ISSN: 0093-691X; 1879-3231
• DOI: 10.1016/S0093-691X(98)00161-7

Three experiments were conducted to evaluate the effects of different antibiotics in a milk-glucose semen extender on motility of equine sperm and elimination of bacteria following storage of extended semen in vitro. In Experiment 1, 7 antibiotics were compared: amikacin, gentamicin, streptomycin, potassium penicillin, sodium penicillin, ticarcillin, and polymixin B. In Experiment 2, 3 antibiotic treatments were compared: potassium penicillin G, amikacin, or a combination of potassium penicillin G and amikacin. In Experiment 3, 3 antibiotic treatments were compared: potassium penicillin G-amikacin, ceptiofur, and a combination of ticarcillin and clavulanic acid (Timentin). Control treatments (antibiotic-free extender) were included in each experiment. Six motility variables were evaluated: percentage of motile sperm; percentage of progressively-motile sperm; percentage of rapidly-motile sperm; mean curvilinear velocity; mean average path velocity; and mean straight-line velocity. In Experiment 1, mean percentages of motile, progressively motile and rapidly motile sperm were lower (P < 0.05) in semen exposed to polymixin B then in other treatments. Mean average-path velocity of sperm in extender containing polymixin B was lower (P < 0.05) than that of all other treatments, with exception of control or ticarcillin. Mean straight-line velocity of sperm in extender containing polymixin B was lower (P < 0.05) than that of all other treatments, with exception of control, streptomycin or ticarcillin. Semen samples containing gentamicin, amikacin, streptomycin, or potassium penicillin were more effective (P < 0.05) at eliminating bacterial growth than those samples containing polymixin B. Semen samples containing gentamicin were also more effective (P < 0.05) at eliminating bacterial growth than those samples containing ticarcillin or sodium penicillin. In Experiment 2, mean percentage of rapidly-motile sperm, and mean curvilinear, average-path, and straight-line velocities were greater (P < 0.05) for potassium penicillin-amikacin than values for all other treatments. In 2 of 3 stallions, an effect of treatment on percentage of motile sperm was detected (P < 0.05). For one stallion, mean motility of potassium penicillin-amikacin was greater (P < 0.05) than that of all other treatment groups. For another stallion, mean motility of the control was lower (P < 0.05) than that of the other treatments. Following storage, potassium penicillin ( 16 18 [89%]) or potassium